Tensegrity structure puzzle

ABSTRACT

A puzzle comprising a cage-like tensegrity structure including a plurality of rigid columns having flexible tension members connected between the opposite ends thereof and having a slot at each end thereof. Each of the columns is slidably supported at opposite ends thereof by the tension members of adjacent columns, which tension members extend through the slots in the columns. A solid or hollow object is positioned within the cage-like structure, the object having an outer dimension which is sufficiently large so as to prevent removal thereof from the structure except when the structure is manipulated to one of a limited number of geometric shapes. According to a preferred embodiment of the present invention, the structure comprises twelve columns and forms a polyhedron having six quadrilateral sides and eight hexagonal sides. The object may be removed from the cage-like structure by contracting four of the six quadrilateral sides and then expanding one of the two remaining quadrilateral sides.

United States Patent Mogilner et al.

154] TENSECRITY STRUCTURE PUZZLE [72] Inventors: Geoffrey A. Mogilner,2070 California St., W., San Diego, Calif. 92110; Rodney D. Johnson, SanDiego, Calif.

[73] Assignee: said Mogilner, by said Johnson [22] Filed: June 11, 1971[21] Appl. No.: 152,055

[56] References Cited UNITED STATES PATENTS 3/1891 Lyon ..273/15611/1962 Fuller ..52/646 OTHER PUBLICATIONS The Dymaxion World ofBuckminster Fuller by Robert W. Marks, publ. by Reinhold PublishingCorp., New York, pages 156- 163 51 Oct. 3, 1972 Primary Examiner-AntonO. Oechsle Att0rneyBernard Kriegel [57] ABSTRACT A puzzle comprising acage-like tensegrity structure including a plurality of rigid columnshaving flexible tension members connected between the opposite endsthereof and having a slot at each end thereof. Each of the columns isslidably supported at opposite ends thereof by the tension members ofadjacent columns, which tension members extend through the slots in thecolumns. A solid or hollow object is positioned within the cage-likestructure, the object having an outer dimension which is sufficientlylarge so as to prevent removal thereof from the structure except whenthe structure is manipulated to one of a limited number of geometricshapes. According to a preferred embodiment of the present invention,the structure comprises twelve columns and forms a polyhedron having sixquadrilateral sides and eight hexagonal sides. The object may be removedfrom the cage-like structure by contracting four of the sixquadrilateral sides and then expanding one of the two remainingquadrilateral sides.

13 Claims, 4 Drawing Figures I PATENTEDUBT 3 I972 SHEET 1 [IF 2INVENTOR. Gt'OFFREYA. MOG/LA/E? B RODNEY a c/Of/NSO/V ATTORNEYSPATENTEDHU 3 I872 SHEET 2 BF 2 INVENTOR. GEOFFREY A M0614 NEE B RQDA/EYD JOHNSON ATTOE/VE'YS TENSEGRITY STRUCTURE PUZZLE BACKGROUND OF THEINVENTION 448,974 issued to Leonard M. Lyon for a Puzzle inl cludingfour concentric rings and a ball which was positioned within the thirdand fourth rings. As stated in the specification, the idea of the puzzlewas to remove the ball from the rings by suitable manipulation thereof.According to the objects of that patent, there was produced anornamental, interesting and inexpensive puzzle which would interest andentertain both adults and children and which was quickly solved by aperson understanding it.

Another early example of this type of puzzle is disclosed in U. S.Patent No. 1,050,141 issued Jan. 14, 1913 to Sam S. Joy. Again, there isshown a puzzle including a number of rings which encircle a ball whichis releasable from the device only by disassembling the rings inaccordance with a predetermined solution.

Another type of decorative puzzle, that has been referred to as a JumboPuzzle, includes a number of wood struts which are held in place bynotches to form a cage. A ball or other object is positioned within thecage. The purpose of the puzzle is to selectively remove certain of thestruts so that the ball can be removed from the cage.

Each of these puzzles, as well as the myriad of other known types ofpuzzles, rely for their appeal on their particular characteristics. Morespecifically, when introducing a puzzle on the market, its ultimatesuccess will be determined by its price, how attractive it is, howinteresting it is to work with, and also its degree of uniqueness.

SUMMARY OF THE INVENTION According to the present invention, there isprovided a novel puzzle of the type discussed previously including acage-like structure enclosing a solid or hollow object such as a ballwhere the structure may be manipulated to a unique geometric shape toremove the ball. The present puzzle differs from heretofore knownpuzzles by forming the cage-like structure in a manner heretoforeunknown in the puzzle art.

Briefly, the present puzzle comprises a cage-like tensegrity structureincluding a plurality of rigid columns having flexible tension membersconnected between the opposite ends thereof and having a slot at eachend thereof. Each of the columns is slidably supported at opposite endsthereof by the tension members of adjacent columns, which tensionmembers extend through the slots in the columns. A solid or hollowobject is positioned within the cage-like structure, the object havingan outer dimension which is sufficiently large so as to prevent removalthereof from the structure except when the structure is manipulated toone of a limited number of geometric shapes. According to a preferredembodiment of the present invention, the structure comprises twelvecolumns and forms a polyhedron having six quadrilateral sides and eighthexagonal sides. The object may be removed from the cage-like structureby contracting four of the six quadrilateral sides and then expandingone of the two remaining quadrilateral sides.

It is therefore an object of the provide a novel puzzle.

It is a further object of the present invention to provide a unique,interesting and decorative puzzle.

It is a still further object of the present invention to provide apuzzle of the type including a cage-like structure enclosing a solid orhollow object.

It is another object of the present invention to provide a puzzleutilizing tensegrity, a structural system incorporating continuoustension and discontinuous compression.

Still other objects, features and attendant advantages of the presentinvention will become apparent to those skilled in the art from areading of the following detailed description of the preferredembodiment constructed in accordance therewith, taken in conjunctionwith the accompanying drawings wherein like numerals designate likeparts in the several figures and wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation view of thebasic building block of the present tensegrity structure including arigid column having a slot at each end thereof and a flexible tensionmember connected between such opposite ends;

FIG. 2 is a plan view of twelve of the columns of FIG. 1 showing themanner in which they may be interconnected to form a polyhedron havingsix quadrilateral sides and eight hexagonal sides;

FIG. 3 is a perspective view of the constructed polyhedron of FIG. 2 inone position shaped as a cube and enclosing a solid or hollow objectsuch as a sphere; and

FIG. 4 shows the manner in which the object may be removed from thetensegrity structure of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present puzzle includes, asone of two major parts thereof, a cage-like tensegrity structure.Accordingly, before discussing in detail the construction of the presentpuzzle, a brief discussion of tensegrity is provided. The wordtensegrity" was coined by the well-known, modern, structural designer,R. Buckminster Fuller, to describe his invention of a structural systemusing continuous tension and discontinuous compression. Tensegritystructures are described in detail in Buckminster Fullers US. Pat. No.3,063,521 as well as in Mr. Fullers book entitled Ideas and Integrities,Prentice Hall Publishing Co., 1963. Articles about Mr. Fullers work and,more specifically, his tensegrity structures, include The Dymaxion Worldof Buckminster Fuller by Robert W. Marks, Southern Illinois UniversityPress; World Design Science Decade 1965-1975, Phase I (1964), Document2, The Design Initiative, World Resources Inventory, Southern IllinoisUniversity, Pages 28 and 35-39; and Portfolio and Art present inventionto News Annual, No. 4, Pages 112-125, The Art Foundation Press, Inc.,1960.

As discussed in these publications, the word tensegrity is a contractionof tensional integrity, a structure the shape of which is guaranteed bythe tensional behaviors of the system and not by the compressionalbehaviors. A tensegrity structure includes a plurality of rigid,column-like compression members having flexible tension membersconnected between the opposite ends thereof, the compression membersbeing held in axially spaced relationship to one another by the tensionmembers. More specifically, the ends of the column-like compressionmembers are connected to the tension members of adjacent compressionmembers. As can be gathered from thepublications cited above, suchtensegrity structures may be constructed to form a polyhedron having anynumber of compression mem- Cord B may be connected between the oppositeends of stick A in any convenient manner. According to a preferredembodiment of the present invention, first and second parallel holes 50and 51 are bored through bers. For example, Buckminster Fullers bookentitled Ideas and Integrities, cited supra, between pages 192 and 193,includes a photograph of a 90 strutminiature tension integrity sphere.

According to the present invention, a tensegrity structure is modifiedso as to provide a unique and interesting puzzle. The modification ofsuch tensegrity structure is two-fold. In the first instance, each ofthe column-like compression members is providedwith a slot at each endthereof so that the tension member connected to one compression memberextends through the slot in an adjacent compression member.

In this manner, each of the compression members is slidably supported atits opposite ends by the tension members of adjacent compressionmembers. Secondly, a solid or hollow object, such as a sphere, a ball, acube, an octahedron or any irregular cobble-shaped object, is positionedwithin the space enclosed by the tensegrity structure. The objectessentially entirely fills such space so that the object is sufficientlylarge to prevent removal thereof from the structure in its normal,uniform orientation. On the other hand, since the compression membersare slidably supported, the structure may be manipulated to form anunlimited number of different geometric shapes. According to the presentinvention, a limited number of such shapes permit removal of the objectso that the modified structure is, indeed, a puzzle.

Referring now to the drawings and, more particularly, to FIG. 1 thereof,there is shown one element with which the present tensegrity structureand puzzle therefrom are to be constructed. More specifically, the firstbasic element of the present puzzle is a rigid, column-like, compressionmember A, having a flexible tension member B connected between theopposite ends thereof. As shown in FIG. 1, tension member B has a lengthwhich is greater than the distance between its attaching points tocolumn A so that it remains loose and manipulatable. As will appearhereinafter, the length of tension member B relative to compressionmember A is not critical, but selected to satisfy the necessity ofkeeping the constructed polyhedron firm when assembled. A ratherelaborate discussion of the theoretical considerations, in a structuralelement, of the length of the tension members compared to the length ofthe compression members may be found in the beforementioned R. B. FullerUS Patent No. 3,063,521.

' cordance with the present invention, such connection is made so thateach stick A is slidably supported at its opposite ends by the cord B ofan adjacent stick A. For this purpose, stick A is constructed by cuttinga slot, 54 and 55, at ends x and y thereof, adjacent holes 50 and 51,respectively, the plane of slots 54 and 55 being perpendicular to holes50 and 51. The width of slots 54 and 55 is approximately equal to thediameter of cord B. More specifically, slots 54 and 55 should be narrowenough to firmly hold cord B, but wide enough to permit cord B toreadily slide through slots 54 and 55.

Although not shown, an alternate technique for connecting the oppositeends of cord B to the ends of stick A is to knot the ends of cord B andto insert cord B into slots 54 and 55. When this is done, the knotsprevent removal of the end of cord B from slots 54 and 55 when cord B isplaced under tension.

According to the present invention, any number of sticks A may beconnected together to form a tensegrity structure in accordance with theteachings of R. Buckminster Fuller. In accordance with the presentinvention, the completed tensegrity structure, forming a polyhedron, maybe manipulated to form an unlimited number of different geometricshapes. An object, generally designated 40, and as shown in FIGS. 3 and4 as a ball, for convenience, is positioned within the space enclosed bythe polyhedron. By manipulating the polyhedron to one of a limitednumber of geometric shapes, ball 40 may be removed.

Referring now to FIGS. 2-4, according to a preferred embodiment of thepresent invention, a preferred configuration for a puzzle includes 12sticks A interconnected to form a polyhedron having six quadrilateralsides and eight hexagonal sides. The completed structure, generallydesignated 45, is shown in FIGS. 3 and includes 12 sticks 1 through 12,sticks 1-12 having cords 21-32, respectively, connected between theopposite ends thereof, in the manner shown in FIG. 1. The manner ofinterconnecting sticks 1-12 to form structure 45 may be best understoodwith reference to FIG. 2. More specifically, a l2-stick polyhedron maybe constructed by starting with stick 1 and extending cord 21 throughthe slot at end x of stick 2. Cord 22 is then extended through the slotat end x of stick 3 and cord 23 is then extended through the slot at endx of stick 4.

Cord 24 is then extended through the slot at end x of stick 1 as well asthrough the slot at end at of stick 5. Cord 25 is then extended throughthe slot at end x of stick 6. Cord 26 is then extended through the slotat end x of stick 7 and cord 27 is extended through the slot at end yofstick 4. Cord 28 is then extended through the slot at end x of stick andcord 30 is extended through the slot at end x of stick 9, as well as theslot at end x of stick 11. Cord 29 is then extended through the slot atend y of stick 6 and cord 32 is extended through the slot at end y ofstick 10. This completes the connections shown in FIG. 2, which enablesticks 1-12 to lie relatively flat.

In order to form the configuration of a polyhedron shown in FIG. 3, thefollowing additional steps are followed. Cord 21 is extended through theslot at end y of stick 7 so that end y of stick 7 is positioned betweenend x of stick 2 and end y of stick 1. Cord 27 is then extended throughthe slot at end y of stick 9 that end y of stick 9 is positioned betweenend yof stick 4 and end y of stick 7. Cord 29 is then extended throughthe slot at end x of stick 12 so that end x of stick 12 is positionedbetween end y of stick 6 and end y of stick 9. Cord 32 is then extendedthrough the slot at end y of stick 1 so that end y of stick 1 ispositioned between end x of stick 12 and end y of stick 10. Cord 22 isthen extended through the slot at end y of stick 12 that end y of stick12 extends between end y of stick 2 and end x of stick 3. Cord 31 is nowextended through the slots at ends y of sticks 2 and 8 so that end y ofstick 2 is closest end x of stick 11 and end y of stick 8 is closest endy of stick 11. Next, cord 25 is extended through the slot at end y ofstick 3 so that end y of stick 3 is closest end y of stick 5.

At this time, any further connections of the sticks and slots willprevent the insertion or removal of ball 40 except when structure 45 ismanipulated to one of a limited number of geometric shapes. Accordingly,at this time, sphere 40 is positioned within tensegrity structure 45.Thereafter, in order to complete structure 45, cord 28 is extendedthrough the slot at end y of stick 5 so that end y of stick 5 ispositioned between end x of stick 10 and end y of stick 8. Finally, cord23 is extended through the slot at end y of stick 11 so that end y ofstick 11 is positioned between end x of stick 4 and end y of stick 3. 1

FIG. 3 shows the appearance of a tensegrity structure 45 having 12sticks and assembled in accordance with the instructions previouslygiven with respect to FIG. 2. However, it will be apparent that theassembly procedure just given is exemplary only and that many more arepossible. From FIG. 3, it may be seen that tensegrity structure 45 formsa polyhedron having six quadrilateral sides and eight hexagonal sides,the quadrilateral sides being arranged in three mutually orthogonaldirections to form a cube having four sides, a top and a bottom. Morespecifically, and with reference to FIG. 3, one quadrilateral sidenamely the front side, designated 60, is formed by cords 21, 22, 23 and24, connected between ends x of sticks 1, 2, 3 and 4. Anotherquadrilateral side, namely the left side as viewed in FIG. 3, designated61, is formed by cords 23, 25, 28 and 31. The right quadrilateral sideas viewed in FIG. 3, designated 62, is formed by cords 21, 27, 29 and32. The top, bottom and rear quadrilateral sides,

designated 63-65, respectively, are formed in a similar manner. Anexample of a hexagonal side, designated 66, is shown in the upper lefthand corner of FIG. 3 and includes cords 23, 24 and 25, each of whichhas two separate sections extending between different ends of differentsticks. Seven more of such hexagonal sides exist.

As explained previously, since each of sticks 1-12 is slidably supportedat opposite ends thereof by cords B connected to adjacent sticks A,tensegrity structure 45 may be manipulated to form an unlimited numberof different geometric shapes, the uniform cube shown in FIG. 3 beingonly one of such shapes. However, in accordance with the presentinvention, and regardless of the number of sticks A used and theparticular polyhedron formed, there is at least one unique geometricshape which will permit the removal of ball 40 from the center ofstructure 45. With a l2-stick polyhedron, as shown in FIGS. 3 and 4,ball 40 may be removed by contracting four of the six quadrilateralsides and then expanding one of the two remaining quadrilateral sides.For example, and with reference to FIG. 4, the ends of sticks l-12 maybe slid along cords 21-32 until the sides 60, 61, 62 and 65 of the cubeare contracted to a small size as shown. Then, by sliding the ends ofsticks 4, 5, 6 and 7 on cords 24, 25, 26, and 27, top 63 of the cube maybe expanded to remove ball 40, as shown in phantom in FIG. 4.

As set forth previously, any number of sticks A may be connectedtogether to form a tensegrity structure in accordance with the teachingsof R. Buckminster Fuller. The completed tensegrity structure, forming apolyhedron, may be manipulated to form an unlimited number of differentgeometric shapes. An object, such as ball 40, may be positioned withinthe space enclosed by the polyhedron. By manipulating the polyhedron toone of a limited number of geometric shapes, the ball may be removed.

By way of example, three sticks A may be subtracted from or added to thestructure shown in FIG. 2 and then such sticks may be interconnected toform a ninestick polyhedron or a l5-stick polyhedron, respectively. Morespecifically, a nine stick polyhedron may be constructed by arrangingsticks 1 through 9 as shown in FIG. 2 and entirely eliminating sticks10, 11, and 12. The directions previously given. for converting thestructure of FIG. 2 to the polyhedron of FIG. 3 would also be applicableto converting sticks 1 through 9 to a nine-stick polyhedron if theinstructions for sticks 10, 1 1 and 12 are applied to sticks 6, 8 and 9,respectively. The resulting polyhedron would have two triangular sides,three quadrilateral sides and six hexagonal sides. As in the case oftensegrity structure 45, the nine stick polyhedron may be manipulated toform an unlimited number of different geometric shapes, at least one ofsuch shapes permitting the removal of an object positioned within thecenter thereof. In the case of the nine stick polyhedron, the object maybe removed by contracting the triangular sides and two of the threequadrilateral sides and then expanding the remaining quadrilateral side.

A l5-stick polyhedron may be constructed by arranging sticks 1 through12 as shown in FIG. 2 and then adding three more sticks 13-15 whichwould be interconnected and connected to sticks 11 and 12 in the exactsame manner as sticks 10-12 are connected to .sticks 8 and 9. Inaddition, the directions previously given for converting the structureof FIG. 2 to the polyhedron of FIG. 3 would also be applicable toconverting sticks 1 through 15 to a l5-stick polyhedron if theinstructions for sticks 10, 11 and 12 are applied to sticks 13, 14 and15, respectively. The resulting polyhedron would have two pentagonalsides, five quadrilateral sides and hexagonal sides. As in the case oftensegrity structure 45, the l5-stick polyhedron may be manipulated toform an unlimited number of different geometric shapes, at least one ofsuch shapes permitting the removal of an object positioned within thecenter thereof. In the case of the l5-stick polyhedron, the object maybe removed by contracting the five hexagonal sides and then expandingone of the two pentagonal sides.

It can therefore be seen that in accordance with the present invention,there is provided a novel puzzle of the type including a cage-likestructure enclosing a solid or hollow object such as a ball where thestructure may be manipulated to a unique geometric shape to remove theball therefrom. The present puzzle differs from heretofore known puzzlesby forming the cagelike structure in a manner heretofore unknown in thepuzzle art. More specifically, and in accordance with the presentinvention, a tensegrity structure is modified so as to be manipulatableinto an unlimited number of different geometric shapes, a limited numberof such shapes permitting removal of the ball therefrom.

While the invention has been described with respect to a preferredphysical embodiment constructed in accordance therewith, it will beapparent to those skilled in the art that various modifications andimprovements may be made without departing from the scope and spirit ofthe invention. For example, although puzzles have been described ascomprising tensegrity structures having nine, 12 or 15 sticks, it willbe apparent to those skilled in the art that a tensegrity structure maybe formed having any number of sticks to form a polyhedron having anynumber of sides. It will be found that any polyhedron so constructedwill have an unlimited number of geometrical shapes in which a limitednumber will permit the removal of a ball positioned thereinside andfilling the space enclosed thereby. Accordingly, it is to be understoodthat the invention is not to be limited by the specific illustrativeembodiment, but only by the scope of the appended claims.

We claim:

1. A puzzle comprising:

a tensegrity structure including a plurality of rigid columns havingflexible tension members connected between the opposite ends thereof,each of said columns being slidably supported at opposite ends thereofby the tension members of adjacent columns to form a polyhedron; and

a solid or hollow object positioned within said tensegrity structure,said object having an outer dimension which is sufficiently large so asto prevent removal thereof from said structure except when saidstructure is manipulated to one of a limited number of geometric shapes.

2. A puzzle according to claim 1 wherein each of said columns has a slotat each end thereof, and wherein the tension member connected to onecolumn extends through the slot in an adjacent column for slidablysupporting said adjacent column.

3. A puzzle according to claim 2 wherein each of said columns has a holebored therethrough at each end thereof, perpendicular to the plane ofsaid slots, and wherein the opposite ends of said flexible tensionmembers are inserted through said holes and knotted to connect saidtension members to said columns.

4. A puzzle according to claim 1 wherein said tensegrity structurecomprises twelve rigid columns, wherein each of said tension membersslidably supports the ends of two of said columns and wherein saidpolyhedron has six quadrilateral sides and eight hexagonal sides.

5. A puzzle according to claim 4 wherein said object may be removed fromsaid structure by contracting four of said six quadrilateral sides andthen expanding one of the two remaining quadrilateral sides, saidcontraction and expansion being achieved by sliding the ends of saidcolumns along said tension members.

6. A puzzle according to claim 4 wherein said columns may be manipulatedrelative to said tension members until said six quadrilateral sides ofsaid polyhedron form a cube having four sides, a top and a bottom.

7. A puzzle according to claim 6 wherein said object may be removed fromsaid polyhedron by manipulating said columns to reduce the size of saidsides of said cube and to increase the size of said top of said cube,and then removing said object through said top of said cube.

8. A puzzle according to claim 1 wherein said tensegrity structurecomprises nine rigid columns,- wherein each of said tension membersslidably supports the ends of two of said columns and wherein saidpolyhedron has two triangular sides, three quadrilateral sides and sixhexagonal sides.

9. A puzzle according to claim 8 wherein said object may be removed fromsaid structure by contracting said triangular sides and two of saidthree quadrilateral sides and then expanding the remaining quadrilateralside, said contraction and expansion being achieved by sliding the endsof said columns along said tension members.

1. A puzzle according to claim 1 wherein said tensegrity structurecomprises fifteen rigid columns, wherein each of said tension membersslidably supports the ends of two of said columns and wherein saidpolyhedron has two pentagonal sides, five quadrilateral sides and tenhexagonal sides.

11. A puzzle according to claim 10 wherein said object may be removedfrom said structure by contracting said five hexagonal sides and thenexpanding one of said two pentagonal sides, said contraction andexpansion being achieved by sliding the ends of said columns along saidtension members.

12. A puzzle according to claim 1 wherein said object is a sphere.

13. A puzzle according to claim 12 wherein said sphere essentiallyentirely fills the space enclosed by said tensegrity structure.

1. A puzzle comprising: a tensegrity structure including a plurality ofrigid columns having flexible tension members connected between theopposite ends thereof, each of said columns being slidably supported atopposite ends thereof by the tension members of adjacent columns to forma polyhedron; and a solid or hollow object positioned within saidtensegrity structure, said object having an outer dimension which issufficiently large so as to prevent removal thereof from said structureexcept when said structure is manipulated to one of a limited number ofgeometric shapes.
 2. A puzzle according to claim 1 wherein each of saidcolumns has a slot at each end thereof, and wherein the tension memberconnected to one column extends through the slot in an adjacent columnfor slidably supporting said adjacent column.
 3. A puzzle according toclaim 2 wherein each of said columns has a hole bored therethrough ateach end thereof, perpendicular to the plane of said slots, and whereinthe opposite ends of said flexible tension members are inserted throughsaid holes and knotted to connect said tension members to said columns.4. A puzzle according to claim 1 wherein said tensegrity structurecomprises twelve rigid columns, wherein each of said tension membersslidably supports the ends of two of said columns and wherein saidpolyhedron has six quadrilateral sides and eight hexagonal sides.
 5. Apuzzle according to claim 4 wherein said object may be removed from saidstructure by contracting four of said six quadrilateral sides and thenexpanding one of the two remaining quadrilateral sides, said contractionand expansion being achieved by sliding the ends of said columns alongsaid tension members.
 6. A puzzle according to claim 4 wherein saidcolumns may be manipulated relative to said tension members until saidsix quadrilateral sides of said polyhedron form a cube having foursides, a top and a bottom.
 7. A puzzle according to claim 6 wherein saidobject may be removed from said polyhedron by manipulating said columnsto reduce the size of said sides of said cube and to increase the sizeof said top of said cube, and then removing said object through said topof said cube.
 8. A puzzle according to claim 1 wherein said tensegritystructure comprises nine rigid columns, wherein each of said tensionmembers slidably supports the ends of two of said columns and whereinsaid polyhedron has two triangular sides, three quadrilateral sides andsix hexagonal sides.
 9. A puzzle according to claim 8 wherein saidobject may be removed from said structure by contracting said triangularsides and two of said three quadrilateral sides and then expanding theremaining quadrilateral side, said contraction and expansion beingachieved by sliding the ends of said columns along said tension members.11. A puzzle according to claim 10 wherein said object may be removedfrom said structure by contracting said five hexagonal sides and thenexpanding one of said two pentagonal sides, said contraction andexpansion being achieved by sliding the ends of said columns along saidtension members.
 12. A puzzle according to claim 1 wherein said objectis a sphere.
 13. A puzzle according to claim 12 wherein said sphereessentially entirely fills the space enclosed by said tensegritystructure.